Door interlock mechanism for enclosed circuit breakers



June 1, 1965 H. l. sTANBAcK ETAL 3,187,124

DOOR INTERLOCK MECHANISM FOR ENCLOSED CIRCUIT BREAKERS Filed Nov, lO. 1961 3 Sheets-Sheet l I Lil INVENToRs /afmisjmfa 3 Sheets-Sheet 2 H. l. STANBACK ETAL DOOR INTERLOCK MECHANISM FOR ENCLOSED CIRCUIT BREAKERS June l, 1965 Filed Nov. 1o. 1961 June l, 1955 H. 1. sTANBAcK ETAL 3,187,124

DOOR INTERLOCK MECHANISM FOR ENCLOSED CIRCUIT BREAKERS 3 Sheets-Sleat 3 Filed NOV. lO. 1961 INVENTORS United States Patent O 3,187,124 DOOR INTERLOCK MECHANISM FOR ENCLOSED CIRCUIT BREAKERS Harris I. Stanback and Harry W. Curtis, both of Lenington, Ky., assignors to Square D Company, Park Ridge, Ill., a corporation of Michigan Filed Nova 10, 1961, Ser. No. 151,542 9 Claims. (Cl. ZOO-50) This invention relates generally to enclosed electrical circuit breakers and 'more particularly to an interlock mechanism between the operating handle of an electrical circuit breaker and the door of an enclosure box therefor.

An object of the invention is to provide an improved deieatable interlock mechanism for preventing unintentional or unauthorized opening of an enclosure door when a handle of a circuit breaker within the enclosure is in the on or circuit-closed position.

Another object is to provide an improved defeatable interlock mechanism for preventing unintentional or unauthorized opening ot either of two enclosure doors of an enclosure containing two circuit breakers when the handle of the associated circuit breaker is in on position.

A further object of the invention is to provide an improved defeatable circuit breaker handle-enclosure door interlock mechanism having a slide on the door cooperable with the circuit breaker handle and lockable in either on or oli position.

A still further object is to provide the combination of an enclosure adapted to house a pair ot circuit breakers arranged in end-toend relationship, the enclosure having a pair of front doors hinged thereto at their remote ends and opening in opposite directions from their adjacent ends, a pair of handle members reciprocaoly mounted respectively in the doors for movement toward and away from each other, the handle members being operatively associable with operating handles of the circuit breakers and having plate members secured thereto on the inner sides of the doors, and an interlock latch member' rotatably mounted between the adjacent ends of the plate members and associable with and dissociable from the plate members by reciprocal movement of the handle members and also by rotary movement or the interlock. latch member.

Other objects will become apparent from the following specication and the accompanying drawings in which:

FIGURE l is `a perspective view of a circuit breaker enclosure` constructed in accordance with this invention;

FGURE 2 is a plan View of the enclosure of FGURE l with portions thereof broken away;

FiGURE 3 is a sectional view in side elevation taken generally as indicated by the' line 3 3 of FGURE 2;

FIGURE 4 is a fragmentary sectional plan view taken generally along the line 4 4 of FGURE 5;

FIGURE 5 is a fragmentary sectional View in front elevation taken generally along the line "5-5 of FIG- URE 4;

Fl'GURE 6 is an exploded perspective view of certain portions of the enclosure;

FIGURE 7 is a fragmentary sectional View in side elevation taken generally along the line '7 7 of FEGURE l; and

FGURE 8 is a fragmentary sectional view in side elevation taken generally along the line 8 8 of FIGURE l.

The enclosure or box 1li includes a top 11 identical with a bottom 12 and a left side 13 identical with a right side 14. The sides are provided with rear mounting flanges 15 and lo, respectively, and with wiring access holes indicated by numerals 17 and i3, respectively. The box 1li is open at the back and is closed at the front by l and when the door Y provided in the door Patented ,lune l, 1965 left and right hand front cover doors 19 front edge portions ofthe top 1l and the ottom l2 are inwardly oitset as shown in FEGURES 3, 7, and 8 and are respectively overlapped by upper and lower flanges on the doors i9 and Zd.

As shown in FIGURE l, a tlange 24 at the outer end portion of the door Ztl is connected to the right side 14 of the box lil by a pair of hinges 25' and 2d, an open position of the door 29 being indicated in FGURE 2 by broken lines. The front edge portion of the right side ifis formed similarly to the front edge portion of the left side 13, which is inwardly offset as shown in FG- URE 2, the offsetting portion being provided with a pair of slots, only one of which is shown, for respectively receiving one portion of each of a pair of hinges similar to the hinges 2S and 26, said portions being secured to the inner surface of the side 13. The other portions of said pair of hinges are respectively secured to the inner surface of a ilange 21 at the outer end portion of the door 19, the iiange 21 being provided with a pair of recesses 22 and 23, as shown in FIGURE, 6, to receive the mating parts of the hinges.

As shown in FGURES 2 and 3, a pair of channelshaaed brackets Z9 and 3d is welded inside the box lil adjacent the respective sides 13 and 1d, the opposite sides of the channels being welded to the top 11 and the bottom i2 of the box, respectively. An insulating base 31 is suitably secured to the brackets 23 and 3@ as by screws 32 threaded into tapped holes in the brackets.

By way of example, a pair of three-pole electrical circuit breakers 34 and 35 is mounted within the box The outer ends of the circuit breakers are respectively secured to a pair of brackets Se' and 37 by means such as screws 3S threaded into tapped holes in the brackets, which in turn are secured to the base El by means such as screws 39. As will be understood, the outer ends of the circuit breakers 34 and 35 are provided with electrical connectors (not shown) for each pole for receiving the ends of electrical conductors (not shown) leading to an electrical load through one of the wiring access holes 1'7 and ld. At the inner ends of the circuit breakers, the respective poles are electrically connected through various strap conductors or branch bus bars, which are secured to the base 31 and shown in broken lines in FlGURE 2, to respective terminal jaws adapted to plug onto main cylindrical bus bars (not shown),

A handle member is reciprocably mounted in a generally rectangular mounting slot 42 (FGURES 4 and 6) and has a flanged plate member provided with anopen-ended slot 5b secured thereto from the inner side of the door l* by means such as screws i4 threaded into bosses d5 provided on the inner end of the handle member. The door 19 has on and oit indicia thereon as shown in FIGURES l and 6, and the handle member di has extensions 47 and i8 thereon on the outer side of the door, the arrangement being such that in the two extreme positions of the handle member within the slot 423, one of the indicia is completely covered and the other is completely uncovered. Further, the iianged plate member d3 is provided with an aperture S7 and the handle member 4l is and is open to the inside of the box pivotable operating handle hollow itl for receiving a i9 of the circuit breaker 3ft, i9 is closed, the indicia on the outer side of the door indicate whether the operating handle 49 of the circuit breaker is in its 011, oli or tripped position, the tripped position being indicated by another indica (not Shown) above the center of the slot 41?. corresponding to a position or" the handle member 41 in which the on and ohr indicia are each pfrtially covener/,12a

Si ered and partially uncovered. The handle member il is provided with a pair of continuous beads do to reduce rictional engagement between the door i9' and the extensions d'7 and rthe door i9 is provided with a slot through which extends a ieg l of an angle bracket 52, the other leg 53 being secured to the inner side of the door by means such as welding. Further, the handle member il is provided with a lower locking liange 5d having a plurality of apertures E5 therethrough alignable with a plurality of apertures Sd provided in the leg 5l for the reception of padlocirs by which the handle member di may be locked in either on7 or oli position to secure the operating handle 4119 of the circuit breaker 3d in a corresponding position.

rihe door il@ is also provided with a slot 59 (FlGUlES 4 and 6) for receiving a spring biased padlock lat-ch dll pivotally mounted on the top lil of the box lll by a rivet 6?, and having a hole 6l therethrough `for reception of a padlock. When the door l@ is locked shut and the handle member il is locked in position, the position of the operating handle 49 of the circuit breaker 2id cannot be changed.

A pair of mounting angle brackets ed and 65 is secured to the 4top il and the bottom l2, respectively, of the box lil by means suchas welding. A tang ed is provided on the horizontal portion of the bracket ed to retain an end of a compression spring o7, the other end of'the spring o7 bearing against a bent tab d8 provided on the latch oli. The latch dll is also provided with a latching surface When the door l@ is closed and the latch dit' rst enters the slot 5%, the leading edge of the latch et) engages the left edge (FlGURE 4) of the slot 59 and the latch titl is pivoted counter-cloclovise on the rivet 62 as the spring is compressed. As the door i9 passes the latching surface 69, the spring d'7 rotates the latch eil clockwiseand the latching surface 69 engages the door 19 adjacent the left edge of the slot S9 to retain it in closed position. The latch o@ may be manually pivoted to disengage the latching surface o9 from the door lll when it is desired to open the door.

Secured to the vertical portions of the brackets 6d and 65 by means such as screws 7l is a larger channel-shaped bracket 7?. having a bottom 73, sides 745 and 75, and outwardly extending llanges 76 and 77 on the tree ends of the sides 7d and 75, respectively, the screws 7l extending through the flanges 76 and 77, respectively, and being threaded into the brackets ed and 65, respectively.

A sheet of insulating material 8@ having bent over edges 3l and El@ is securex t the inner side of the bracket 72, as best shown in FlGURE 7, by means such as a nonconducting screw S3 threaded into the upper portion of the flange 'To and a similar screw @Il threaded into the lower portion of the llange 7'7, the screws 33 and Sd preferably being'formed of a material such as nylon.

rEhe sides 7d and 7S and the outer edges of the bottom 755 ot the bracket 72 are cut away to provide slots indicated by numerals S7 and dit, respectively. An interlock latch member 9d, shown best in FGURES 5 and 6, is pivotally mounted on the inner side of the bottom 73 of the bracket 72 by means of a rivet 9i having an outer slotted head adapted to receive the tip of a screwdriver. The rivet -"l is pivotable in a round hole in the bottom 73 of the bracket 72, but is provided with a reduced diameter portion at its inner end (FlGURE 8) which is swagcd into a square hole in the interlock latch member @il to key the latch member @il to the rivet.

An inwardly projecting tang 92 (FGVURE. 5) is provided on the side 75 of the bracket 72 and an offset tang 93 is provided on a lower portion of `the interlock latch member 9@ for the mounting of a compression spring 94 which biases the latch member 9@ clockwise in FIGURE 5, an upper portion of the latch member @il engaging a stop in the form of the portion of the side 75 of the bracket 72 immediately above the slot ri`he interlock latch member may be pivoted through a limited arc ot movement counter-clockwise in FIGURE 5 against the torce of the spring @d by rotation of the rivet @l with a screw driver, the movement being limited by engagement of the upper portion of the latch member @il with the portion of the side 74 of the bracket 72 immediately above the slot S7.

The interlock latch member 9i? has an arm 95 extending outwardly lof the slot S7, a bent projection or interfering portion 96 being formed on an edge of the outer end thereof.

in FlCURES 4 and 5, the handle member di and the operating handle il@ are shown in oil position wherein the lian ged plate member i3 and the projection llo on the arm '535 of the interlock latch member @il are in a noninteriering relationship to each other and the door l@ may be opened upon release of the latch dil. When the handle member il and the operating handle 49 are moved to the right to on position, the flanged plate member d3 will be shifted to the dotted line position `thereof indicated in llGUlrlE 5 wherein the projection @d and the portion or" the ilanged plate member above the openendcd slot are in an interfering relationship to each other and the door l@ cannot be opened merely upon the release of the latch titl. However, an authorized person desiring to open the door l@ when the handle member il and operating handle i9 are in on position may do so after iirst rotating the interlock latch member 9i? counter-clockwise to lower the projection 96 into alignment with the slot Sil.

The operation described above with respect to the door il@ is equally applicable with respect to the door Ztl, for which a complete separate description of cooperating parts and of the operation is omitted. It will be surlicient to point out that the door Ztl is provided with a handle member dla, a plate member 43a, and a latch @da corresponding to ythe handle member dit, the plate member 43, and the latch o@ of the door 19, and further that the interlock latch member 9@ has an arm 955e and projection 96a `corresponding to the arm 95 and projection 96. The plate member 43a, shown in FIGURE 2 in broken lines, is provided with a slot corresponding to a slot Stia shown in the plate member i3 in FGURES 5 and 6, and rotation of the interlock latch member dissociates the projections 96 and 96a from the plate members 43 and 43a respectively.

Various modifications may be made in the structure disclosed without departing from the spirit and scope of the invention as set forth in the appended claims.

We claim:

ll. The combination comprising:

(a) a box adapted to house an electrical circuit breaker mountable therein,

(b) said box having a front cover door connected thereto by a hinge,

(c) said door having an elongated generally rectangular mounting slot therein,

(d) a handle member slidably mounted in said mounting slot and operable from an outer side of said door for sliding movement toward and away from said hinge,

(e) a plate member secured to said handle member on an inner side of said door for sliding movement with said handle member,

(f) said plate member having an aperture therethrough and said handle member being hollow and open toward the inside of said box to receive a pivotable operating handle of said electrical circuit breaker when said electrical circuit breaker is mounted in said box, whereby said operating handle may be operated by sliding movement of said handle member,

and Y (g) an interlock latch member mounted in said box Ye, 187, 121i adjacent an end of said plate member remote from said hinge, l

(h) said interlock latch member having an interfering portion located between said plate member and the inner side of said door and engageable with a portion of said plate member to interfere with opening of said door when said handle memberis in a position adjacent an end of said mounting slot remote from said hinge, and

(i) said interfering portion of said interlock latch member being spaced from said plate member in a direction away from said hinge to permit opening of said door without interference when said handle member is in a position adjacent an end of 'said mounting slot adjacent said hinge.

2. The combination comprising:

(a) a box adapted to house an electrical circuit breaker mountable therein,

(b) said box having a front cover door connected thereto by a hinge,

(c) said door having an elongated generally rectangular mounting slot therein,

(d) a handle member slidably mounted in said mounting slot and operable from an outer side of said door for sliding movement toward and away from said hinge,

(e) a plate member secured to said handle member on an inner side of said door forl sliding movement with said handle member,

(f) said plate member having an aperture therethrough and vsaid handle member being hollow and open toward the inside of said box to receive a pivotable operating handle of said electrical circuit breaker when said electrical circuit breaker is mounted in said box, whereby said operating handle may be operated by sliding movement of said handle member,

(g) said plate member having an open-ended slot therein adjacent an end thereof remote from said hinge, and

(h) an interlock latch member pivotally mounted in said box adjacent the end of said plate member having said open-ended slot therein,

(i) said interlock latch member having an interfering portion located between said plate member and the inner side of said door and engageable with a portion of said plate member adjacent said open-ended slot to interfere with opening of said door when said handle member is in a position adjacent an end of said mounting slot remote from said hinge,

(j) means for pivoting said interlock latch member from outside said box to move said interfering portion into alignment with said open-ended slot and permit opening of said door without interference even though said handle member is in said position adjacent said end of said mounting slot remote from said hinge, and

(k) said interfering portion of said interlock latch member being spaced from said plate member in a direction away from said hinge to permit opening of said door without interference when said handle member is in a position adjacent an end of said mounting slot adjacent said hinge.

3. The combination claimed in claim 2, including biasing means urging said pivotally mounted interlock latch member toward a position wherein it is out of alignment with said open-ended slot in said plate member.

4. The combination claimed in claim 2, including stop means limiting pivotal movement of said interlock latch member in opposite directions.

5. The combination claimed in claim 2, including a spring-biased padlock latch pivotally mounted in said box and extending outwardly thereof, and wherein said door is provided with a slot for receiving an outer end of said padlock latch, said outer end of said padlock latch hav- 6 ing a hole therethrough for reception of a padlock by which said door may be locked closed.

6. The combination claimed in claim 2, including padlock attaching means on said handle member and door adapted to receive a padlock for locking said handle member against movement with respect to said door.

7. ri`he combination comprising:

(a) a box adapted to house a pair of electrical circuit breakers mountable therein,

(b) said box having a pair of front cover doors connected respectively thereto adjacent opposite ends thereof by a pair of hinges,

(c) said doors having a pair of mounting slots respectively therein,

(d) a pair of handle members reciprocably mounted respectively in said mounting slots in said doors, each handle member being operable from an outer side of its respective door for movement toward and away from the hinge of its respective door,

(e) a pair of plate members, each plate member being secured to one of said handle members on an inner side of its respective door,

(f) each of said plate members having an aperture therethrough and each of said handle members being hollow and open toward the inside of said box to receive a pivotable operating handle of one of said electrical circuit breakers whensaid electrical circuit breakers are mounted in said box, whereby the operating handles of the circuit breakers may be respectively operated by said handle members, and

(g) each of said plate members having an open-ended slot therein adjacent an end thereof remote from the hinge of its respective door,

(h) and an interlock latch member pivotally mounted in said box between said plate members,

(i) said interlock latch member having a pair of interfering portions each located between one of said plate members and the inner side of its respective door and each engageable with a portion of its respective plate member adjacent the open-ended slot therein to interfere with the opening of its respective door when its respective handle member is in a position adjacent an end of its respective mounting slot remote from its respective hinge,

(j) means for pivoting said interlock latch member from outside said box to move each of said interfering portions into alignment with the open-ended slot in its respective plate member and permit opening of its respective door without interference even though its respective handle member is in said position adjacent an end of its respective mounting slot remote from its respective hinge, and

(k) each of said interfering portions of said interlock latch member being spaced from its respective plate member in a direction away from its respective hinge to permit opening of its respective door without interference when its respective handle member is in a position adjacent an end of its respective mounting slot adjacent its respective hinge.

8. The combination comprising:

(a) an enclosure adapted to house a pair of circuit breakers mountable therein in endto-end relationship with operating handles thereof extending toward the front of said enclosure,

(b) said enclosure having a pair of front doors hinged thereto at their remote ends and opening in opposite directions from their adjacent ends,

(c) a pair of handle members respectively slidably mounted on said doors for movement toward each other to a first position and away from each other to a second position,

(d) said handle members being operatively connected respectively to said operating handles of said circuit breakers when said circuit breakers are mounted in alarmes `said enclosure and having a pair of plate members secured respectively thereto on the inner sides of said doors for sliding movement with said handle members, and

(e) an interlock latch member rotatably mounted in said enclosure between adjacent ends of said plate members for rotary movement between iirst and second positions independently of the positions of said handle members and having a pair of interfering portions respectively interfering With said plate members to prevent opening of said doors when said handle members are respectively in said first positions thereof and said interlock latch member is in 9. The combination comprising: (a) an enclosure adapted to house a circuit breaker mountable therein with an operating handle thereof extending toward the front of said enclosure,

(b) said enclosure having a front door connected thereto by a hinge,

(c) a handle member slidably mounted on said door for movement away from said hinge to a rst position and toward said hinge to a second position,

(d)l said handle-member being operatively connected to said oper-ating handle of said circuit breaker when said circuit breaker is mounted in said enclosure and having a plate member secured thereto on the inner side of said door for sliding movement with said handle member, and

(e) an interlock latch member rotatably mounted in said enclosure adjacent an end of said plate member remote from said hinge for rotary movement between first and second positions independently of the position of said handle member and having an interfering portion interfering with said plate member toprevent opening of said ydoor When said handle member and said interlock latch member are respectively in said first positions thereof, the interfering relationship between said interlock latch member and said plate member being changeable to a non-interfering relationship by movement of said handle member to said second position thereof While said interlock latch member remains in said first position thereof and also by rotary movement of'said interlock latch member to said second position thereof while said handle member remains in said iirst position thereof.

References Cited by the Examiner UNITED STATES PATENTS 2,550,125 4/51 Schueler et al ZO--SO 2,789,169 4/57 Duvall et al. 200-50 3,028,459 4/62 Norden 200-50 BERNARD A. GILHEANY, Primary Examiner. 

9. THE COMBINATION COMPRISING: (A) AN ENCLOSURE ADAPTED TO HOUSE A CIRCUIT BREAKER MOUNTABLE THEREIN WITH AN OPERATING HANDLE THEREOF EXTENDING TOWARD THE FRONT OF SAID ENCLOSURE, (B) SAID ENCLOSURE HAVING A FRONT DOOR CONNECTED THERETO BY A HINGE, (C) A HANDLE MEMBER SLIDABLY MOUNTED ON SAID DOOR FOR MOVEMENT AWAY FROM SAID HINGE TO A FIRST POSITION AND TOWARD SAID HINGE TO A SECOND POSITION, (D) SAID HANDLE MEMBER BEING OPERATIVELY CONNECTED TO SAID OPERATING HANDLE OF SAID CIRCUIT BREAKER WHEN SAID CIRCUIT BREAKER IS MOUNTED IN SAID ENCLOSURE AND HAVING A PLATE MEMBER SECURED THERETO ON THE INNER SIDE OF SAID DOOR FOR SLIDING MOVEMENT WITH SAID HANDLE MEMBER, AND (E) AN INTERLOCK LATCH MEMBER ROTATABLY MOUNTED IN SAID ENCLOSURE ADJACENT AN END OF SAID PLATE MEMBER REMOTE FROM SAID HINGE FOR ROTARY MOVEMENT BETWEEN FIRST AND SECOND POSITIONS INDEPENDENTLY OF THE POSITION OF SAID HANDLE MEMBER AND HAVING AN INTERFERING PORTION INTERFERING WITH SAID PLATE MEMBER TO PREVENT OPENING OF SAID DOOR WHEN SAID HANDLE MEMBER AND SAID INTERLOCK LATCH MEMBER ARE RESPECTIVELY IN SAID FIRST POSITIONS THEREOF, THE INTERFERING RELATIONSHIP BETWEEN SAID INTERLOCK LATCH MEMBER AND SAID PLATE MEMBER BEING CHANGEABLE TO A NON-INTERFERING RELATIONSHIP BY MOVEMENT OF SAID HANDLE MEMBER TO SAID SECOND POSITION THEREOF WHILE SAID INTERLOCK LATCH MEMBER REMAINS IN SAID FIRST POSITION THEREOF AND ALSO BY ROTARY MOVEMENT OF SAID INTERLOCK LATCH MEMBER TO SAID SECOND POSITION THEREOF WHILE SAID HANDLE MEMBER REMAINS IN SAID FIRST POSITION THEREOF. 